This invention relates to the field of cutout bits for use with rotary tools. During a construction project it may be desirable to create large wall areas with drywall. To efficiently perform this task, large drywall panels are initially secured to wood studs and/or other supporting structure thereby covering planned openings in the large wall areas such as those for electrical outlet boxes and window and door frames. Thereafter, openings are cut in the large drywall panels to expose the electrical outlet boxes, window and door frames, and/or other underlying structures. The underlying structures typically provide templates or guides for cutting the corresponding openings in the drywall. Indeed, a drywall cutting tool is lightly urged against the peripheries of the underlying structures while maneuvering the cutting tool therearound to create the openings. This results in time savings when compared to creating such openings in the large drywall panels prior to securing the drywall to the support structure.
A conventional twist drill bit typically will not move smoothly around the periphery of an underlying structure; if guided against the structure it will typically abrade or cut into the structure, thereby undesirably dulling itself and marring the underlying structure. Additionally, a conventional twist drill bit may perform well in the axial direction, but typically performs inadequately when moved in the lateral direction since its flute configuration is configured primarily for drilling in the axial direction.
Consequently, special tools have been developed for cutting openings in drywall and performing similar operations on wood and/or other materials. Such tools are generally used as bits in routers. These bits typically must cut axially through a workpiece and then laterally (i.e., in directions perpendicular to their lengths) through the workpiece to make the desired openings. To this end, such a bit has historically included a shank for insertion into a router, a tip portion with one or more axial cutting features, a smooth non-fluted guide portion at the proximal end of the tip portion for guiding the bit against an underlying structure, and possibly more lateral cutting features extending between the guide portion and the shank. While omissions of axial drilling features from the guide portions of some such bits may have facilitated tracing the bits around underlying structures, the lack of axial drilling features has also undesirably limited drilling efficiencies of the bits.
Thus, there is a need for a cutout bit that provides improved axial drilling features in a guide portion of the bit that can nevertheless trace smoothly around underlying structures.